Refining the understanding of the crosstalk between auxin and indolic defense compound metabolism in Arabidopsis thaliana to improve transferability of the model system to major crops

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dc.contributor.advisorPeer, Wendy Aen_US
dc.contributor.authorHouse, Lillyannaen_US
dc.contributor.departmentPlant Science and Landscape Architecture (PSLA)en_US
dc.contributor.publisherDigital Repository at the University of Marylanden_US
dc.contributor.publisherUniversity of Maryland (College Park, Md.)en_US
dc.date.accessioned2024-07-02T05:36:16Z
dc.date.available2024-07-02T05:36:16Z
dc.date.issued2024en_US
dc.description.abstractThe main natural auxin, indole-3-acetic acid (IAA), modulates a diversity of plant growth and developmental responses through the tight regulation of auxin biosynthesis and inactivation, transport, and signaling. Evidence that analogous auxin metabolic pathways contributing to programmed and plastic development exist amongst different plant species, points to the necessity for refinement of the current understanding of auxin metabolism in Arabidopsis thaliana to improve its transferability as a model system to major crops. Evaluation of the current understanding of auxin biology in plants and analytical tools available for the visualization and quantification of auxin reveal several gaps of knowledge. This work seeks to address this by 1.) elucidating the specific roles of DIOXYGENASE FOR AUXIN OXIDATION 1 and 2 (DAO1 and DAO2) in the oxidative catabolism of IAA and IA-conjugates and functionality of oxidized IAA (oxIAA), 2.) clarifying the function of ATP-BINDING CASSETTE subfamily B (ABCB) transporters and the interplay of auxin, brassinolide, and ethylene in apical hook development and 3.) investigating the possibility of an analogous auxin metabolic pathway involving the natural auxin, phenylacetic acid (PAA), in Oryza sativa. Herein, it is shown that DAO2 activity is similar to DAO1 and assists in the regulation of auxin homeostasis under high auxin conditions and DAO1 is both soluble and plasma membrane associated. Additionally, oxIAA functions as a weak “anti-auxin” to modulate processes like apical hook development, where a subset of ABCB transporters is found to function in auxin mobilization downstream of ethylene signaling and brassinolide transport. The detection of PAA was achieved using LC-MS, however further method development is required for accurate quantification of PAA in rice tissue samples. Application of previous and new knowledge pertaining to the crosstalk between auxin and indolic defense metabolism in Arabidopsis revealed a seemingly analogous pathway in rice whereby phenyl acetonitrile (PAN) is converted to PAA, likely via nitrolases. The results presented herein, refine the understanding of auxin metabolism in Arabidopsis and exemplify the use of a model system in elucidating similar pathways in agriculturally significant crops.en_US
dc.identifierhttps://doi.org/10.13016/tvcj-ubnr
dc.identifier.urihttp://hdl.handle.net/1903/33029
dc.language.isoenen_US
dc.subject.pqcontrolledPlant sciencesen_US
dc.subject.pquncontrolledABCBen_US
dc.subject.pquncontrolledAuxin metabolismen_US
dc.subject.pquncontrolledDAOen_US
dc.subject.pquncontrolledIAAen_US
dc.subject.pquncontrolledLC-MSen_US
dc.subject.pquncontrolledPAAen_US
dc.titleRefining the understanding of the crosstalk between auxin and indolic defense compound metabolism in Arabidopsis thaliana to improve transferability of the model system to major cropsen_US
dc.typeThesisen_US

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